1. Sedimentary BasinSedimentary basins correspond to depressions in the upper parts of the Earths crust, generally occupied by a sea or an ocean. These depressions are initiated by geodynamic phenomena often associated with the displacement of lithosphere plates. The basement of the sedimentary basins is formed of crust made up of igneous rocks (granite on the continents and basalt in the oceans). Sedimentary rocks such as clays, sandstones, carbonates or massive salt have accumulated in these basins over geological time. Sedimentation generally involves a process extending over tens of millions of years, at a rate of several millimetres per year on average. Chiefly due to the weight of the deposits, the ongoing geodynamic processes and the accumulation of sediments lead to deformation and progressive sinking of the underlying crust. This accentuates the initial depression, giving rise. To a sedimentary filling that is often many kilometers thick. This deepening of the basin, which is known as subsidence, results from the combined effects of tectonic movements and sedimentary overburden. In extreme cases, subsidence can reach as much as 20 km.The tectonic setting is the premier criterion to distinguish different types of sedimentary basins:1. Extensional basins occur within or between plates and are associated with increased heat flow due to hot mantle plumes.2. Collisional basins occur where plates collide, either characterized by subduction of an oceanic plate or continental collision.3. Transtensional basins occur where plates move in a strike-slip fashion relative to each other.

2. Basin AnalysisBasin analysis involves interpretation of the formation, evolution, architecture and fill of a sedimentary basin by examining geological variables associated with the basin. It provides a foundation for extrapolating known information into unknown regions in order to predict the nature of the basin where evidence is not available. It helps the exploration and development of energy, mineral and other resources (e.g. water, brines, etc.). That may occur within sedimentary basins.A basin model is built on a framework of geological surfaces that are correlated within the basin.Stratigraphic framework can be expressed in terms of rock type (lithostratigraphy), fossil content (biostratigraphy), age (chronostratigraphy), or rock properties such as seismic velocity (seismic stratigraphy).3. The Importance of Basin Analysis on Petroleum Industry is Decided By Geographic location. kind of basin Tectonic history. The sedimentary history, and the effects of thermal changes on these sediments. Content, age, thickness and facies of the sediments of primary petroleum concern, such as the reservoir, cap rock and source beds.Basin analysis encompasses many topics since it integrates several fields within geology. But it emphasis on evaluation of strata that fill stratigraphic basins.

Major approaches: Basin formation and character, plate tectonics. Basins fill characteristics, processes and evolution. Basin analysis techniques. Description and correlation of stratigraphic basin fill(sequence stratigraphy). Petroleum System. Prospect generation and evaluation.

4. Purpose of Basin Analysis Determine the physical chronostratigraphic framework by interpreting sequences, systems tracts, and parasequences and/or simple sequences on outcrops, well logs, and seismic data and age date with high resolution biostratigraphy. Construct geohistory, total subsidence and tectonic subsidence curves on sequence boundaries. Complete tectonostratigraphic analysis including: Relate major transgressive-regressive facies cycles to tectonic events. Relate changes in rates of tectonic subsidence curves to plate-tectonic events. Assign a cause to tectonically enhanced unconformities. Relate magmatism to tectonic subsidence curve. Map tectonostratigraphic units. Determine style and orientation of structures with tectonostratigraphic.

5. Stages of Basin Analysisa. Initial Stage AnalysisDuring the initial stages of exploration the broad framework of a basin may be worked out with the help of satellite imagery, aerial photo, surface geological data, gravity, magnetic and seismic data. Stratigraphic and sedimentological information obtained from wells and Seismic data helps in reconstructing the depositional history and inter relating the structural patterns with sedimentation. The stratigraphic and record of the basin full is the basis for interpreting the casualties of hydrocarbon generation and accumulation. From knowledge of the worldwide sedimentary basins, certain associational characteristics of hydrocarbon accumulation, their distribution in space and time and the potential of the total basin are broadly indicated.

b. Middle Stage AnalysisThe second stage of basin analysis is reached during the advanced phases of hydrocarbon exploration, when the tectonic framework, nature of sedimentary fill, structural styles and habitat of oil/gas are better known and more refined and quantitative analysis becomes feasible. Detailed lithological and paleoenvironmental studies, paleogeomorphic, structural and paleotectonic analysis, working out depositional systems, geochemical studies and identification of petroleum systems are the key elements at this stage. This results in a more precise definition of oil and gas generation and accumulation zones and their relationship with the stratigraphic and tectonic settings in various parts of the basin leading to a predictive exploration model.

c. Final Stage AnalysisThe final stage is basin analysis, which forms the major part of exploration activity, is the search wit the help of the above exploration model, to locate favourable structural, stratigraphic, paleogeomorphic and other subtle prospects for exploratory drilling.The information generated at various stages may require re-interpretation, due to improvement in techniques or concepts or discovery of new plays in the basin. Basin analysis is thus, a continuous process carried out in stages, directed towards discovery of hydrocarbons.With this background, it is clear that basin analysis requires a synergistic approach, with different geoscientific activities playing their pivotal role during stages of work. The detailed scheme of basin analysis encompassing the major activities, sub-activities, while the flow chart following it provides a broad overview.